Olga Neuwirth was the subject of the second of the London Sinfonietta's portrait concerts this season. The 43-year-old Austrian is best known in Britain for Lost Highway, her music-theatre piece based on David Lynch's film, which ENO staged in 2008. But as the Sinfonietta programme showed, she is a hard composer to pin down.

All the pieces were UK premieres, though one of them, the 2006 trumpet concerto Miramondo Multiplo, had been heard in the UK before in its larger-scale orchestral version. The main event was the "songplay in nine fits", Hommage à Klaus Nomi, Neuwirth's tribute to the countertenor Klaus Nomi, a cult figure in the 1980s New York underground, with a repertoire from Purcell and Schumann to Judy Garland and Donna Summer.

Neuwirth has arranged nine of Nomi's best-known numbers and punctuated them with a couple of silent-film clips of his performances. The soundworld builds on the synthesis-laden textures of the original recordings, with the voice amplified and multitracked. It's curious, surreal and just a bit too long, but above all it's a wonderful tour de force for the counter-tenor Andrew Watts, resplendent in his sequinned tie, who revealed what a versatile artist he is – a Birtwistle premiere at last summer's Proms, and everything from Dido's Lament to a high-camp version of The Witch Is Dead here.

Watts had also been the wonderfully accomplished soloist in Five Daily Miniatures, settings of Gertrude Stein that fracture already gnomic texts into isolated phonemes and wordless sounds. Alistair Mackie was the tireless trumpeter in Miramondo Multiplo, which certainly sounds more focused with ensemble instead of full orchestra, but still doesn't reveal what meaning its references to Sondheim, Handel and Miles Davies have beyond private significance to the composer herself.